The present invention relates to an office equipment, and more particularly to an electrical reading guide device for use in typing by a typist.
The electrical reading guide device of prior art for use in typing by a typist is composed mainly of a reading guide plate and a vertical positioning device which in turn comprises a main body and a fastening plate. The main body comprises therein a reversible motor serving to actuate a gear set. The gear set and the gear strip located on the back of the guide groove of the plate body coordinate to form a basic rail for positioning. A guide rule, which is used to point out the way for a typist to read the manuscript which she or he is typing, is connected with the fastening plate of the positioning device and is therefore capable of making a synchronous up-and-down movement along with the positioning device.
The electrical reading guide device of prior art described above has two major inherent defects, which are explicitly expounded hereinafter.
The up-and-down movement of the positioning device of prior art is made possible by means of a simultaneous engagement of the gear strips of the guide groove actuated by two gear sets. The contact area between the gear set and the gear strips is so substantially large that their frictional engagement always brings about a loud and uncomfortable noise.
The components of the electrical reading guide device of prior art are expensive and difficult to come by because they are manufactured in accordance with certain sets of specifications. In addition, the task of assembling components of device is tedious.